import { presetFonts, type Preset } from '@cdx-ui/styles';
import { buildWebFontStylesheetUrl } from './override/webFonts';

const LINK_ID_PREFIX = 'cdx-theme-editor-fonts-';

function buildGoogleFontsUrl(families: readonly string[]): string {
  return buildWebFontStylesheetUrl(
    families.map((family) => ({
      family,
      weights: [400, 500, 600, 700],
      italic: true,
    })),
  );
}

function injectLink(id: string, href: string): void {
  const existing = document.getElementById(id);
  if (existing) {
    if ((existing as HTMLLinkElement).href === href) return;
    existing.remove();
  }

  const link = document.createElement('link');
  link.id = id;
  link.rel = 'stylesheet';
  link.href = href;
  document.head.appendChild(link);
}

function removeLink(id: string): void {
  document.getElementById(id)?.remove();
}

/**
 * Load the display fonts for a given preset via Google Fonts CDN.
 * Removes previously loaded preset fonts before injecting.
 */
export function loadPresetFonts(preset: Preset): void {
  const presets: Preset[] = ['poise', 'prestige', 'pulse'];
  for (const p of presets) {
    if (p !== preset) {
      removeLink(`${LINK_ID_PREFIX}${p}`);
    }
  }

  const families = presetFonts[preset];
  const url = buildGoogleFontsUrl(families);
  injectLink(`${LINK_ID_PREFIX}${preset}`, url);
}

/**
 * Load platform fonts shared across all presets (Inter, IBM Plex Mono).
 */
export function loadPlatformFonts(): void {
  const url = buildGoogleFontsUrl(['Inter', 'IBM Plex Mono']);
  injectLink(`${LINK_ID_PREFIX}platform`, url);
}

/**
 * Remove all theme editor font links from the document.
 */
export function cleanupFontLinks(): void {
  const presets: Preset[] = ['poise', 'prestige', 'pulse'];
  for (const p of presets) {
    removeLink(`${LINK_ID_PREFIX}${p}`);
  }
  removeLink(`${LINK_ID_PREFIX}platform`);
}